Introduction
MemSFT specializes modern large language models with an external parametric
memory. This checkpoint contains the Qwen3-8B memory trained on
Biology-Instructions. The memory learns to approximate retrieval-based teacher
distributions over domain SFT data. At each decoding step, a learned
token-level router combines the next-token distributions of the frozen base
model and memory. This checkpoint is an auxiliary memory, not a standalone
chat model. Its key advantages are:
- Plug-and-Play: Attaches to a frozen backbone without modifying its
parameters or architecture.
- Strong Specialization: Improves domain performance with negligible
degradation in general capabilities.
- Cross-Scale Reuse: Works with Qwen3 backbones from 8B to 235B-A22B
without retraining the memory for each backbone.
Quick Start
The 14B + 8B example is intended for a CUDA GPU with sufficient memory to
load both models in BF16.
1. Install
git clone https://github.com/LUMIA-Group/MemSFT.git
cd MemSFT
conda create -n memsft-generate python=3.10 pip -y
conda activate memsft-generate
python -m pip install -e .
python -m pip install \
"torch>=2.4,<2.7" \
"transformers==4.51.3" \
"huggingface-hub==0.35.3" \
"accelerate>=0.34,<2"
2. Load the base, memory, and router
from pathlib import Path
import torch
from huggingface_hub import snapshot_download
from transformers import AutoModelForCausalLM, AutoTokenizer
from memsft.router.adaptive_memdec import AdaptiveMemoryDecoder
device = torch.device("cuda:0")
base_id = "Qwen/Qwen3-14B"
memory_id = "Jiarui-Wang/MemSFT-Qwen3-Bio-Memory-8B"
router_repo = "Jiarui-Wang/MemSFT-Qwen3-Routers"
router_subdir = "Qwen3-14B-Bio-M8B-Router"
router_root = snapshot_download(
repo_id=router_repo,
revision="v1.0.0",
allow_patterns=[f"{router_subdir}/*"],
)
router_path = str(Path(router_root) / router_subdir)
tokenizer = AutoTokenizer.from_pretrained(
base_id,
revision="40c069824f4251a91eefaf281ebe4c544efd3e18",
)
base = AutoModelForCausalLM.from_pretrained(
base_id,
revision="40c069824f4251a91eefaf281ebe4c544efd3e18",
torch_dtype=torch.bfloat16,
low_cpu_mem_usage=True,
).to(device).eval()
memory = AutoModelForCausalLM.from_pretrained(
memory_id,
revision="v1.0.0",
torch_dtype=torch.bfloat16,
low_cpu_mem_usage=True,
).to(device).eval()
vocab_size = len(tokenizer)
base.resize_token_embeddings(vocab_size)
memory.resize_token_embeddings(vocab_size)
base.requires_grad_(False)
memory.requires_grad_(False)
model = AdaptiveMemoryDecoder(
base_lm=base,
knn_generator=memory,
router_path=router_path,
router_device=device,
).eval()
model.set_tokenizer(tokenizer)
3. Generate
sequence = (
"MKSILIEKPNQLAIVEREIPTPSAGEVRVKVKLAGICGSDSHIYRGHNPFAKYPRVIGHEFFGVIDAV"
"GEGVESARVGERVAVDPVVSCGHCYPCSIGKPNVCTTLAVLGVHADGGFSEYAVVPAKNAWKIPEAVA"
"DQYAVMIEPFTIAANVTGHGQPTENDTVLVYGAGPIGLTIVQVLKGVYNVKNVIVADRIDERLEKAKE"
"SGADWAINNSQTPLGEIFTEKGIKPTLIIDAACHPSILKEAVTLASPAARIVLMGFSSEPSEVIQQGI"
"TGKELSIFSSRLNANKFPIVIDWLSKGLIKPEKLITHTFDFQHVADAISLFEQDQKHCCKVLLTFSE"
)
prompt = (
r"<PROTEIN> "
+ sequence
+ r" </PROTEIN> What is the EC number associated with the enzymatic "
r"function of this protein? Please put the final enzyme within \boxed{} "
r"using an EC number such as ECx.x.x.x, and separate multiple entries "
r"with commas."
)
messages = [{"role": "user", "content": prompt}]
prompt_text = tokenizer.apply_chat_template(
messages,
tokenize=False,
add_generation_prompt=True,
enable_thinking=False,
)
inputs = tokenizer(prompt_text, return_tensors="pt").to(device)
with torch.inference_mode():
output_ids = model.generate(
**inputs,
do_sample=False,
max_new_tokens=32,
eos_token_id=tokenizer.eos_token_id,
pad_token_id=tokenizer.eos_token_id,
)
answer = tokenizer.decode(
output_ids[0, inputs["input_ids"].shape[1]:],
skip_special_tokens=True,
)
print(answer)
Example output:
UniProtKB annotates Escherichia coli K-12 RspB
(P38105) with EC
1.1.1.-. For comparison, using the same prompt and deterministic generation
configuration, Qwen3-14B alone predicts EC 4.2.1.22. The outputs were
reproduced in BF16 on NVIDIA A800 80GB GPUs.
The same Qwen3-8B Biology-Instructions memory is reused with each base model;
each pairing uses its corresponding router.
Table with columns: Base model, Biology-Instructions ↑, General ↑| Base model | Biology-Instructions ↑ | General ↑ |
|---|
| Qwen3-8B + MemSFT | 42.84 | 81.15 |
| Qwen3-14B + MemSFT | 42.92 | 83.62 |
| Qwen3-32B + MemSFT | 42.82 | 85.33 |
| Qwen3-235B-A22B + MemSFT | 42.05 | 87.11 |
Compatible Pairing
The example above uses:
- base:
Qwen/Qwen3-14B
- memory:
Jiarui-Wang/MemSFT-Qwen3-Bio-Memory-8B
- router:
Jiarui-Wang/MemSFT-Qwen3-Routers/Qwen3-14B-Bio-M8B-Router
MemSFT prefers tensor-only .safetensors router checkpoints. Legacy .pt
checkpoints should be loaded only from trusted sources; the MemSFT loader uses
PyTorch's restricted weights_only=True mode for compatibility.
Intended Use and Limitations
This checkpoint is intended for reproducing MemSFT and for augmenting
compatible Qwen3 base models on Biology-Instructions tasks. It should be used
with the router matching the selected base/memory pair. Performance outside
the evaluated model combinations and domains has not been established.
License
This MemSFT checkpoint is released under the Apache License 2.0. Upstream
models, software, and datasets remain subject to their respective licenses
and terms.
Citation
If you find MemSFT helpful in your research, please consider citing:
@misc{wang2026memsftmitigatingalignmenttax,
title={MemSFT: Mitigating Alignment Tax with an External Parametric Memory},
author={Jiarui Wang and Xiang Shi and Jiaqi Cao and Rubin Wei and Xiquan Wang and Hao Sun and Jingzhi Wang and Zhiqi Yang and Qipeng Guo and Bowen Zhou and Zhouhan Lin},
year={2026},
eprint={2607.25614},
archivePrefix={arXiv},
primaryClass={cs.LG},
url={https://arxiv.org/abs/2607.25614},
}
For questions and discussions, feel free to email
wangjiarui1@sjtu.edu.cn.